Abstract: Shaft lining in thick weakly consolidated strata is featured with large deformation and repeated damage after repair. Based on the concrete strength failure criterion under biaxial compression and analytical solution for spatially axisymmetric problem of a thick-walled cylinder, we obtained the limit value of damage of the shaft lining in Xinjulong coal mine. We selected three formations to carry out monitoring by a multi-layer automatic deformation monitoring system for the auxiliary shaft in Xinjulong coal mine, and evaluated the status of the lining. Results show that the deformation of the shaft lining under the condition of ultimate failure is 2.369 mm. The shaft lining located in the border of the bottom aquifer and the bedrock subjects to the most severe deformation, about 82.5% of the deformation limit. The shaft lining deformation increment fluctuates in a certain range belonging to elastic deformation. Finally, we inversed the stress state according the deformation value of the shaft lining. The obtained value of additional stress is lower than the ultimate compressive strength. Long-term project practice shows that the deformation monitoring results could reflect the real stress condition of the shaft lining. Moreover, the monitoring system could realize real-time dynamic evaluation of the shaft lining status.

Key words: weakly cemented strata, shaft lining, deformation, monitoring system, condition evaluation